The consumer type AA or AAA sized nickel metal-hydride (NiMH) or nickel cadmium (NiCd) rechargeable batteries have widely been in use. Various electrical appliances, such as digital cameras, video recorders, AV equipment, notebook computers, PDAs, cellar phones and toys, require high capacity and reliability AA or AAA sized rechargeable battery cells for operation. There is an ongoing demand for the battery charging time to be as short as possible.
However, a faster charge requires the use of a larger charging current, but a larger current may result in overheating of the batteries. As is known, overheating may damage the battery or reduce its capacity and number of life cycles. In general, a NiMH battery will only have part of its capacity available if the body rises to a temperature over about 60° C. during charging. The life cycle will also be shortened under this condition.
The subject invention seeks to mitigate or at least alleviate such problems by providing an improved battery charger.